The field of single cell analysis has grown considerably in the last decade. Typically, the existing methods for single cell analysis require isolation of the single cell.
U.S. Pat. No. 8,362,446 describes an apparatus which can perform an optical scanning of a biological mass (e.g. a blood sample) and identify rare objects (such as, e.g., circulating cancer cells or any single cell). The blood sample is placed on a glass disc in a single layer (monolayer) in which they are attached to the surface through chemical bonds. During the scanning, the glass disc is rotated. By use of such a system it would be beneficial to be able to lift such selected objects (e.g. circulating cancer cells) from the disc into a container or another system. This container or system will make it possible to subject the object to further analysis or characterization, e.g. relating to DNA, mRNA or genes.
One problem with such systems is that it is typically difficult to loosen them from the surface without damaging them. A typical procedure is to scrape them off from the surface mechanically whereby they normally integrate and the structure becomes damaged. This damage is often problematic and destructive to the further characterization. When cells are scraped off from a surface, they will often disintegrate (crumble), thus increasing the likelihood of obtaining mixed material from other cells. Certain properties of a cell, such as, e.g., mRNA, are very delicate and will be very easily damaged if the cell disintegrates.
There are various methods/systems on the market which are developed for lifting cells from a glass surface. The best known are called laser manipulation (laser micro manipulation). Here laser light is used on the one hand for cutting cells from a tissue section and on the other hand for lifting and transporting the isolated cell from the surface and into a container. These systems may be designed in two ways. (1) The cells are placed directly on the glass, and the laser light releases the cell from the surface through the supply of heat. (2) A thin membrane is placed on top of the glass on which the cells are attached. Here the laser light is used both for cutting out the membrane and for lifting up the cell which is still stuck to the membrane and placing it into a container. The laser is typically placed beneath the glass surface, and the direction of the laser light lifts the cell upwards. A substantial problem with these laser-based systems is that they are very expensive and complex to use.
The apparatus described in U.S. Pat. No. 8,362,446 is normally used for blood cells, which, contrary to tissue cells, are normally loose individuals. When it is desired to lift selected cells from the surface, it will normally not be necessary to cut the individual cell from a coherent tissue of cells (tissue section). It is only necessary to release the cell from the surface.
DE patent No. 19714987 C1 describes an instrument for collecting cells from a glass surface. This instrument uses a combination of a steel capillary and a concentric glass capillary. The steel capillary is designed to scrape a cell off the medium. This scraping function will often destroy the integrity of the cell because the cell is at the same time stuck firmly to the surface.